File system checking and recovery (C/R) tools play a pivotal role in increasing the reliability of storage software, identifying and correcting file system inconsistencies. However, with increasing disk capacity and data content, file system C/R tools notoriously suffer from long runtimes. We posit that current file system checkers fail to exploit CPU parallelism and high throughput offered by modern storage devices. To overcome these challenges, we propose pFSCK, a tool that redesigns C/R to enable fine-grained parallelism at the granularity of inodes without impacting the correctness of C/R's functionality. To accelerate C/R, pFSCK first employs data parallelism by identifying functional operations in each stage of the checker and isolating dependent operation and their shared data structures. However, fully isolating shared structures is infeasible, consequently requiring serialization that limits scalability. To reduce the impact of synchronization bottlenecks and exploit CPU parallelism, pFSCK designs pipeline parallelism allowing multiple stages of C/R to run simultaneously without impacting correctness. To realize efficient pipeline parallelism for different file system data configurations, pFSCK provides techniques for ordering updates to global data structures, efficient per-thread I/O cache management, and dynamic thread placement across different passes of a C/R. Finally, pFSCK designs a resource-aware scheduler aimed towards reducing the impact of C/R on other applications sharing CPUs and the file system. Evaluation of pFSCK shows more than 2.6x gains of e2fsck and more than 1.8x over XFS's checker that provides coarse-grained parallelism.

中文翻译：

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使用 pFSCK 加速文件系统检查和修复

文件系统检查和恢复 (C/R) 工具在提高存储软件的可靠性、识别和纠正文件系统不一致方面发挥着关键作用。然而，随着磁盘容量和数据内容的增加，文件系统 C/R 工具的运行时间很长。我们假设当前的文件系统检查器无法利用现代存储设备提供的 CPU 并行性和高吞吐量。为了克服这些挑战，我们提出了 pFSCK，这是一种重新设计 C/R 的工具，可在不影响 C/R 功能正确性的情况下以 inode 的粒度实现细粒度并行。为了加速 C/R，pFSCK 首先通过识别检查器每个阶段的功能操作并隔离相关操作及其共享数据结构来采用数据并行性。然而，完全隔离共享结构是不可行的，因此需要限制可扩展性的序列化。为了减少同步瓶颈的影响并利用 CPU 并行性，pFSCK 设计了流水线并行性，允许 C/R 的多个阶段同时运行而不影响正确性。为了为不同的文件系统数据配置实现高效的流水线并行，pFSCK 提供了对全局数据结构的更新排序、高效的每线程 I/O 缓存管理以及跨 C/R 的不同传递的动态线程放置的技术。最后，pFSCK 设计了一个资源感知调度器，旨在减少 C/R 对共享 CPU 和文件系统的其他应用程序的影响。pFSCK 的评估显示 e2fsck 的增益超过 2.6 倍，比 XFS 的增益超过 1.8 倍